A virtually closed system is treated as open and compared to known results. The classic experiment of Clement and Desormes provides the conceptual framework for this open system approach in determining the molar heat capacity ratios, lambda. This alternate view, extends the theoretical treatment beyond the first law of thermodynamics for closed systems, utilizing both an energy and entropy balance, offering an opportunity to test the value of this perspective against historical methods. The arbitrary choice of the system and its boundaries is shown to affect the nature and magnitude of the work terms, along with the accompanying simplifications in the fundamental equation. (Contains 1 figure.)